Design of Nanotechnological Carriers for Ocular Delivery of Mangiferin: Preformulation Study

Abstract

(1) Background: Mangiferin (MGN) is a natural compound, showing anti-inflammatory and antioxidant activities for the potential treatment of eye diseases. The poor physicochemical features of MGN (low solubility and high instability) justify its nanoencapsulation into nanostructured lipid carriers (NLC) to improve its ocular bioavailability. (2) Methods: Firstly, MGN-NLC were prepared by the high shear homogenization coupled with the ultrasound (HSH-US) method. Finally, unloaded and MGN-loaded NLC were analyzed in terms of ocular tolerance. (3) Results: MGN-NLC showed good technological parameters suitable for ocular administration (particle size below 200 nm). The ORAC assay was performed to quantify the antioxidant activity of MGN, showing that the antioxidant activity of MGN-NLC (6494 ± 186 μM TE/g) was higher than that of the free compound (3521 ± 271 μM TE/g). This confirmed that the encapsulation of the drug was able to preserve and increase its activity. In ovo studies (HET-CAM) revealed that the formulation can be considered nonirritant. (4) Conclusions: Therefore, NLC systems are a promising approach for the ocular delivery of MGN.

Keywords: eye diseases; mangiferin; nanostructured lipid carriers; ocular drug delivery.

Figure 1

Chemical structure of mangiferin (MGN).

Figure 2

(a,b) Transmission electron microscopy images of MGN-NLC. The scale bar represents 200 nm.

Figure 3

Calorimetric curves, in heating mode, of unloaded NLC and MGN-NLC.

Figure 4

Calorimetric curves, in heating mode, of MLV containing a different molar fraction of MGN.

Figure 5

Calorimetric curves, in heating mode, of MLV left in contact with the solid MGN at increasing times.

Figure 6

Calorimetric curves, in heating mode, of MLV left in contact with unloaded NLC at increasing times.

Figure 7

Calorimetric curves, in heating mode, of MLV left in contact with MGN-NLC at increasing times.

Figure 8

Pictures of chorioallantoic membrane (CAM) after the application of (A) 0.1 M NaOH so-lution (positive control), (B) 0.9 wt% NaCl solution (negative control), (C) unloaded NLC and (D) MGN-NLC.